Installing Valves

Installing valves 

Remove all valve grinding paste fully after grinding.

Information 

• The valves cannot be touched up afterwards. 
• The valves can be grinded using commercially available valve grinding paste. 

1. Apply a small a fit of valve grinding paste to the valve seat.
2. Oil the valve stem of a new valve and insert it into the valve guide from the combustion chamber. Push the valve in until it is seated securely in the valve seat of the cylinder head.
3. Grind in the valve using the commercially available valve grinding tool (with rubber suction cup) by means of rotary movements. To do this, hold the valve grinder between the palms of both hands and press against the valve seat with rotating movements.
   Fig 1: Grinding Valve Seat

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4. Carry out the grinding operation for each valve that is replaced. Check for leaks using some fuel and installed spark plugs. The fuel must not escape through the valve seat. Carefully remove valve grinding paste.
5. Fit valve lock.
   Fig 2: Locking Valves

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6. Replace valve-stem seals. Details at → 156319 REMOVING AND INSTALLING VALVE-STEM SEALS ON 4.8- LITRE DFI ENGINES 
7. Fit valve springs, concave washer and valve keys. To do this, place valve springs (there are two in the exhaust valve in the turbo engine) on the bottom concave washer. Place top concave washer in position.

   Information 

   The mechanic must practise for use of the assembly cartridge to be effective. Some repetitions must be made to ensure that the valve keys are correctly held in place.

8. Insert valve keys into the assembly cartridge.
   1. 8.1. Press the spring washer of the assembly fixture downwards -1-  and insert the valve key -2-  with the narrow end pointing downwards.
      Fig 3: Inserting Valve Keys Into Assembly Cartridge

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   2. 8.2. Ensure that the valve keys fit symmetrically and are inserted as far as they will go in the tool. The spring washer automatically locks the valve keys in place.
   3. 8.3. Place the assembly cartridge -2-  onto the centre of the assembly fixture. Observe installation position of the valve keys -1-  .
      Fig 4: Fitting Assembly Cartridge

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   4. 8.4. Press the assembly cartridge against the spring force onto the assembly fixture. The knurled screw moves forward. When doing so, turn the knurled screw back and forth until the valve keys snap into place. Repeat as required.
      Fig 5: Pressing Assembly Cartridge Onto Assembly Fixture

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   5. 8.5. Make sure the valve keys are held symmetrically in place in the assembly cartridge -1-  .
      Fig 6: Installing Valve Keys In Assembly Cartridge

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9. Place the valve key assembly cartridge onto the cylinder head (same as removal of valve) and position it on the top spring plate.
10. Press the assembly cartridge with the lever (assembly bar) against the force of the valve-spring and keep pressed. The knurled screw moves forward. When doing so, turn the knurled screw back and forth until the valve keys snap into place. Install valve keys. Repeat as required.
    Fig 7: Turning Knurled Screw

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11. When installing the valve keys, check their correct positioning.